Bovine TB in France
Although control measures to tackle bovine tuberculosis (bTB) in cattle have been successful in many parts of Europe, this disease has not been eradicated in areas where Mycobacterium bovis circulates in multi-host systems. Bouchez-Zacria et al (2023) (https://doi.org/10.1186/s13567-023-01168-8) analysed the resurgence of 11 M. bovis genotypes defined based on spoligotyping and mycobacterial interspersed repeat units-variable number tandem repeats (MIRU-VNTR) detected in 141 farms between 2007 and 2019, in an area of southwestern France where wildlife infection was also detected from 2012 in 65 badgers. The authors used a spatially-explicit model to reconstruct the simultaneous diffusion of the 11 genotypes in cattle farms and badger populations. Effective reproduction number R was estimated to be 1.34 in 2007–2011 indicating a self-sustained M. bovis transmission by a maintenance community, although within-species Rs were both <1, indicating that neither cattle nor badger populations acted as separate reservoir hosts. From 2012, control measures were implemented, and a decrease of R below 1 was observed. Spatial contrasts of the basic reproduction ratio suggested that local field conditions may favour (or penalise) local spread of bTB upon introduction into a new farm. Calculation of generation time distributions showed that the spread of M. bovis has been more rapid from cattle farms (0.5–0.7 year) than from badger groups (1.3–2.4 years). Although eradication of bTB appears possible in the study area (since R<1), the model suggests it is a long-term prospect, because of the prolonged persistence of infection in badger groups (2.9–5.7 years). Supplementary tools and efforts to better control bTB infection in badgers including, for instance, vaccination, appear necessary.
Leptospira
Pathogenic Leptospira spp. are zoonotic bacteria that infect wild and domestic animals. Humans contract leptospirosis directly through contact with infected animals or indirectly from contaminated water or soil. In mammalian reservoirs, the pathogen can colonise renal tubules for lengthy periods and persistently contaminate the environment through urine. Cattle have been reported to shed several serovars; with Hardjo the most common serovar found in cattle. Without clinical manifestations, the infection can spread within a herd, impairing productivity, and putting workers like farmers, abattoir operators and veterinarians at risk. The dynamics of pathogenic Leptospira shedding was studied in six dairy herds in southern Chile by Monti et al (2023) (https://doi.org/10.1186/s13567-023-01190-w). Various intermittent urine shedding patterns were found, with elimination periods between 79 and 259 days and bacterial loads ranging from 3×104 to 4.4×104 bacteria/mL. This study is reported to be the first to assess the various urine shedding patterns and loads of pathogenic leptospires shed through the urine of naturally-infected dairy cows. In addition, the study suggests that vaccination does not prevent cattle infection, although it influences loads of pathogenic leptospires excreted in urine. The authors claim the study provides a great awareness of asymptomatic animal carriers in an endemic area and will contribute to improving disease control and designing better prevention strategies. This is interesting to read, since work done in the 1980s and early 1990s here in the UK similarly raised awareness, but one wonders if risk awareness amongst the UK farming community is declining since we seem to talk about this pathogen far less now than we once did.
Communicating without words
Uptake of advice and the ability to facilitate change on-farm are key elements for successful veterinary practice. However, having the necessary clinical skills and knowledge is not enough to achieve this: effective communication skills are essential for veterinarians to realise their advisory role by exploring and understanding the farmer's worldview. Research of verbal aspects of veterinarian communication supports the use of a relationship-centred communication style. However, these authors saw the need to study how veterinarian–farmer non-verbal communication (NVC) can influence interactions and their outcomes. In this study by MacGillivray et al (2023) (https://doi.org/doi.org/10.3168/jds.2022-22479), the authors considered which aspects of NVC should be measured, and how, to provide an essential first step toward understanding the significance of NVC for veterinarians working in dairy practice. Eleven video recordings of routine consultations in the UK were analysed for farmer and veterinarian NVC. The NVC attributes with established links to positive patient and client outcomes from medical and social science studies were chosen, and a methodology developed for their measurement, by adapting measures typically used in NVC research. Each consultation was segmented into intervals defined by the main activity and location on farm: introduction, fertility examination, discussion and closing. This approach allowed the authors to analyse the content more consistently, establish which aspects of NVC featured within each interval, and whether the activity and location influenced the observed NVC. They measured 12 NVC attributes, including body orientation, interpersonal distance, head position and body lean, which have been shown to influence empathy, rapport, and trust: key components of relationship-centred communication. Future research should seek to establish the significance of NVC in effective communication between veterinarian and farmer, building upon findings that show it is possible to measure non-verbal attributes. Veterinarians may benefit from becoming skilled non-verbal communicators and have more effective conversations during routine consultations, motivating farmers to make changes and improve herd health.